This invention relates to an improved peak flow meter. Peak flow meters are used for measuring the peak air flow of a patient's exhalation. Peak flow meters permit physicians to track changes in the patient's respiratory condition and diagnose potential or existing breathing problems. Patients also use peak flow meters outside a doctor's office to monitor their own condition on a regular basis.
Existing peak flow meters provide various ways of measuring peak air flow. For example, U.S. Pat. No. 4,421,120 discloses a peak respiratory flow monitor with multiple openings and a reed that generates a sound when air flow reaches an adjustable threshold. While the device disclosed in the '120 patent is relatively simple to use and indicates a peak flow threshold, it does not provide detailed measurement readings to a patient.
An example of a peak flow meter providing more detailed information to a user is U.S. Pat. No. 5,246,010. As is common with mechanical peak flow meters, the '010 patent discloses a peak flow meter with an indicator responsive to internal pressure as generated by peak air flow. Three adjustable markers are adjacent to a scale along which the indicator moves. A personal zone calculator for determining where to place the adjustable markers is provided. Although the '010 patent provides patients with more detailed information, it is relatively complicated to set up and use.
Accordingly, there is a need for a peak flow meter that provides detailed, accurate information and is simple to set up and use.